How does this work?

So I was just reading online about a house going on the market for $155 million. Further down the article it talked about Trump's home that he's asking $125 million. So I went to a mortgage calculator and the monthly payment on a simple mortgage for that much is $729,000. Who pays that as a mortgage? How can they?! Am I missing something. Well clearly nobody would mortgage that much... There's something about the world of super high finance that I'm totally missing. I can't imagine that someone has enough liquid assets to be able to outright purchase a house for $125 million. So how does that work??